{"id":"CVE-2021-28713","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-28713","generatedAt":"2026-10-27T23:36:29.403Z","title":"Rogue backends can cause DoS of guests via high frequency events T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Xen offers the ability to run PV backends in regular…","description":"Rogue backends can cause DoS of guests via high frequency events T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Xen offers the ability to run PV backends in regular unprivileged guests, typically referred to as \"driver domains\". Running PV backends in driver domains has one primary security advantage: if a driver domain gets compromised, it doesn't have the privileges to take over the system. However, a malicious driver domain could try to attack other guests via sending events at a high frequency leading to a Denial of Service in the guest due to trying to service interrupts for elongated amounts of time. There are three affected backends: * blkfront patch 1, CVE-2021-28711 * netfront patch 2, CVE-2021-28712 * hvc_xen (console) patch 3, CVE-2021-28713","published":"2022-01-05T17:15:09.000Z","lastModified":"2026-06-17T03:46:51.000Z","status":"Modified","sourceIdentifier":"security@xen.org","cvss":{"version":"3.1","score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H"},"cwe":[],"affected":["xen/xen","debian/debian linux"],"epss":{"score":0.00332,"percentile":0.2615,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.33%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://lists.debian.org/debian-lts-announce/2022/03/msg00011.html","tags":["Third Party Advisory"],"source":"security@xen.org"},{"url":"https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html","tags":["Third Party Advisory"],"source":"security@xen.org"},{"url":"https://www.debian.org/security/2022/dsa-5050","tags":["Third Party Advisory"],"source":"security@xen.org"},{"url":"https://www.debian.org/security/2022/dsa-5096","tags":["Third Party Advisory"],"source":"security@xen.org"},{"url":"https://xenbits.xenproject.org/xsa/advisory-391.txt","tags":["Patch","Vendor Advisory"],"source":"security@xen.org"},{"url":"https://lists.debian.org/debian-lts-announce/2022/03/msg00011.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2022/dsa-5050","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2022/dsa-5096","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://xenbits.xenproject.org/xsa/advisory-391.txt","tags":["Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-28713","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}